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Re: Some questions about the Shark driver

Originally Posted by Goldigger

Hi Steve,
Sorry im confused.. How do i get the 14-16volts output i require?
Is is depentdant on Vin and current that is set by the trimpot?

Hi,
it's a little confusing at first. You don't need to worry about the output voltage of 14-16v except when you are choosing which driver and batteries you use. When you are working out how to drive led's it's the current that you need to control. Current = brightness. You are choosing a drive current of 1 amp. So you set the driver to always supply 1 amp by adjusting the trimpot (this adjusts the output current).
The driver will then always supply 1 amp. So, in your example you'd wire the Ostar up to the driver and it will supply 1 amp which means that it will be giving a supply voltage of whatever the led need in order to draw one amp - say 15 volts (which reduces as the led warms up). If you then wired another Ostar in series with the one you've already got, the driver will still try to supply 1 amp to both, which would mean it will automatically up the output voltage to c. 30 volts.
If you then hooked it up instead to 5 led's that needed 18 volts to draw 1 amp, it would give them 18 volts. It will give the led's exactly the voltage they need in order to draw 1 amp. This is very important because as led's heat up, the voltage they "drop" reduces for the same current. eg I have a Cree MC-E. If I drive it at 1 amp it will "drop" around 14 volts at first, but as it gets hotter it only needs around 13.2 volts to draw 1 amp. So, if I feed it a constant 14 volts, it will start off drawing 1 amp but as it gets warmer it will be receiving more voltage than it needs so it will draw more current, probably enough to burn it out because it will continue to get hotter and hotter.
You need to consider your battery voltage also because a boost driver needs an input supply voltage that is less than the voltage it is churning out. In your example the Ostar needs 14 - 16v so you must keep your battery voltage below 14v. You'll need to attach your Shark to a heatsink to get rid of the heat that it will produce. The lower your battery voltage drops, the harder the Shark will have to work to supply the 14-16v, so the more current it will draw from the battery, and the hotter it will get.
It sounds very complicated - probably because of my crap explanation. I'll PM you my email address and we can go through it all offline if you like. All the info is on here in various places if you do a search anyway.

Re: Some questions about the Shark driver

Does anyone have a wiring diagram for attaching a remora. I have found the resistor part, but have seen different information on what you are supposed to jumper when the trim pot is removed. Also what kind of switch is used and where is it connected on the Remora, or on the shark?

Re: Some questions about the Shark driver

Thanks, looked through the forums, but not your site. I am assuming then that a spst or a momentary NC switch is required between Vin and Vout then and not anywhere on the remora with a momentary switch

Re: Some questions about the Shark driver

Yes, the resistors and switches are a great way to set the brightness levels. It is simplier than the uP version and is more direct where you can know in advance (physical) what brightness level you will have before you turn on the power.

Jumpering Blue Shark

When jumpering J1 on my blue shark the soldering pad close to the edge of the board came off. Where else can I attach the wire to get J1 jumpered (can’t see it anymore because the picture at the shoppe isn’t sharp enough and I don’t have another blue shark anymore to compare). Thanks.

Re: Some questions about the Shark driver

Got one.

The blue shark says it's rated to about 32V. What would happen if, for example, I connected 12 LED's to it for a draw easily in excess of 40V? Would something go pop or would the board voltage regulate to about 32V? What I want to do is connect 2x MC-E's in series which will be getting perilously close to 32V. No problems with supply voltage and current (12V automotive, less than 2A), just wondering what will happen if load exceeds max. voltage.

Re: Some questions about the Shark driver

Originally Posted by Jarl

Got one.

The blue shark says it's rated to about 32V. What would happen if, for example, I connected 12 LED's to it for a draw easily in excess of 40V? Would something go pop or would the board voltage regulate to about 32V? What I want to do is connect 2x MC-E's in series which will be getting perilously close to 32V. No problems with supply voltage and current (12V automotive, less than 2A), just wondering what will happen if load exceeds max. voltage.

Re: Some questions about the Shark driver

Testing the Blue Shark or Shark Buck.

The technique I use to test the converter board safely should be done prior to any hookup to ensure the converter is fully functional. Most boards shipped mid this year or so have been pre-tested. Still, pre-tested or not I would still test it before using it.

The ideal method for the Shark buck is the use a power supply set at 6V with the current limiting set to 150mA or so. At this current there is little risk in damaging the converter board even if there is a problem.

Wire the converter board to the power supply and an LED. Any standard 1W,3W LED with Vf around 3.2V will be fine for this test. Apply power. If the LED lights and the power supply current limits turn the trim pot till the power supply comes out of current limit. Verify the trim pot adjusts from near zero LED brightness to something brighter until current limiting is reached. If there is control over this range the converter is fully functional.

The same test setup can be used to safely test the Blue Shark except the LED load needs to be three LEDs in series. Again after power is applied the LEDs should light up and you should be able to turn the trim pot to get the LEDs to goto near zero light output and have some brightness control range up to the point the power supply current limits. If this work you can raise the current limit to 300mA and verify control over a larger range.

If you don't have a power supply the next best thing is to use something like a 10-20 ohm 2W power resistor in series with a 6V battery pack. The 40 ohm resistor should provide enough protection even if the converter is shorted.

Re: Some questions about the Shark driver

[QUOTE=LED Zeppelin;2705368]Mike, the A123s are capable of lots of current.
This is an excerpt from another thread post I made some time ago that might help with a pot/Shark mod:How to wire multiple Sharks to one dimming control:

Hi LED Zeppelin and others,

I have built a underwater fluorescence lamp with blue OSTARs and 2 Blue Sharks http://www.uni-due.de/zoophysiologie/Seiten/GRUNZScuba2.HTM
see also my homepage http://www.uni-due.de/zoophysiologie/ Some people asked me if the lamp could be provided with an external dimming control. The problem is that I don't like to accept an additional hole in the body of the lamp. Some commercial lamps work with an external magnetic switch, which triggers a dimmer inside the lamp. In my case this dimmer (Poti) circut should be connected with the Shark instead of the Poti. One possibilty would be to use this sort of dimmer https://www1.elfa.se/data1/wwwroot/w...A/07377443.pdf A switch in form of a REED contact (inside) connected with the dimmer could be operated from the outside with a magnetic switch (no hole necessary).
Do you have further comments if my suggestions are realistic. Would be glad to hear other and better solutions. with best regards Horst

Re: Some questions about the Shark driver

I will comment on one thing for sure. A power when turned on rises from zero to the target voltage. This slow rise in the supply voltage will turn on the converter around 2.8V or so and the converter will try to ramp up the output to the LEDs very quickly. This will in almost all cases trip the overcurrent on the power supply and in many cases cause it to remain in this faulted condition. My supplies do this all the time and I use an external push button switch in series with the supply to power the converter boards. This will apply the power supply at full voltage and not ramp up the input to the converter board.

Re: Some questions about the Shark driver

Originally Posted by dat2zip

I will comment on one thing for sure. A power when turned on rises from zero to the target voltage. This slow rise in the supply voltage will turn on the converter around 2.8V or so and the converter will try to ramp up the output to the LEDs very quickly. This will in almost all cases trip the overcurrent on the power supply and in many cases cause it to remain in this faulted condition. My supplies do this all the time and I use an external push button switch in series with the supply to power the converter boards. This will apply the power supply at full voltage and not ramp up the input to the converter board.

Wayne

I'm confused about the metal vise comment in Cindy's post. Do you have any thoughts about that Wayne? There isn't anything conductive on or near the edge of the board that I could see.

Re: Some questions about the Shark driver

Hi TB,

I have got the same problem with Blue Shark like you. In January I had bought 10 pcs of Blue Shark and every single one don´t work.
My testing circuit consist of Lion 11,1V battery and modul with 4 x Cree XRE-R2. Led´s light very poor. Input current is about 150mA and trimpot has no influence to light. I think that Blue Shark run only as direct drive.

Re: Some questions about the Shark driver

There is a problem with this batch.

Resistor R4 is the wrong value and sets the max output voltage limit to 11.4V. My functional test fixture only has 3 LEDs on it and everything works fine since 3 LEDs Vf is less than 11.4V so the functional test did not catch this.

We will start the process of changing R4 on all Blue Sharks built in Jan 2010 and we apologize for this error.

If you have a blue shark shipped in the last month we need you to contact the shop so we can work out getting this corrected.

Re: Some questions about the Shark driver

Originally Posted by Sleza

Hi TB,

I have got the same problem with Blue Shark like you. In January I had bought 10 pcs of Blue Shark and every single one don´t work.
My testing circuit consist of Lion 11,1V battery and modul with 4 x Cree XRE-R2. Led´s light very poor. Input current is about 150mA and trimpot has no influence to light. I think that Blue Shark run only as direct drive.

Sleza

Bummer

The trim pot on my Blue Shark would dim the LED down to the off state, however 140mA ~ 150mA was all I could get out of the driver.

Re: Some questions about the Shark driver

Originally Posted by dat2zip

There is a problem with this batch.

Resistor R4 is the wrong value and sets the max output voltage limit to 11.4V. My functional test fixture only has 3 LEDs on it and everything works fine since 3 LEDs Vf is less than 11.4V so the functional test did not catch this.

We will start the process of changing R4 on all Blue Sharks built in Jan 2010 and we apologize for this error.

If you have a blue shark shipped in the last month we need you to contact the shop so we can work out getting this corrected.

Wayne

Wayne, I received an email from Cindy and she told me my metal pin vise probably shorted the board and it would not be covered under warranty. Has this changed?